Zinc is an essential trace mineral, which, next to iron, is the second most abundant. Humans digest 20%-40% of the zinc that is found in foods, like red meats, poultry and seafood. Plant and dairy sources are not as well absorbed. The fiber in vegetables lessens the absorption of zinc and research has shown that dairy and egg sources of zinc are also not the best sources of zinc. It is no surprise then that several studies have shown that vegetarians often have a lower intake of zinc due to the avoidance of meat, seafood and poultry.

The human body requires various nutrients to run smoothly. Zinc is also essential for tissue growth and repair, for fetal development and sperm production, wound healing, taste acuity, proper thyroid function, blood clotting and cognitive functions.

The muscle is where much zinc is stored but it is also found in the skin, red and white blood cells, liver, pancreas, kidney and retina of the eye. Recently, a study in the Archives of Ophthalmology claimed that if those people who were at an elevated risk for age-related macular degeneration took zinc along with an antioxidant, it could help prevent or delay the lose of sight. The researchers found that currently there are approximately 1.75 million people 40 years or older living with age-related macular degeneration in the U.S. Also, more than 7 million people were found to have a substantial risk of developing the disease.

Since zinc is stored in the body, when the diet is low in zinc, there may be a marginal deficiency necessitating a multivitamin vitamin with zinc. However, over supplementation, from supplements or fortified foods, can actually interfere with other important minerals, such as iron, magnesium and copper. A study, found that those people who took a 45 milligrams supplement had decreased magnesium balance. An example over supplementing may extend to taking too many zinc lozenges to care for cold symptoms. More of nutrients, is not better, and can be harmful. That is why the Food and Nutrition Board of the Institute of Medicine set an upper limit of safety for zinc at 40 milligrams daily for adults.

Rarely, is someone in America deficient in zinc, unless they have an inadequate diet, such as in the cases of the elderly, alcoholics, vegetarians and low-income children. However, in developing countries zinc deficiency is more common and may play a role in reduced life expectancy.

Zinc Content of Common Foods

Food

Zinc (milligrams)

Oysters, #.5 oz. (cooked)

39

Beef Pot Roast 3.5 oz cooked

8.5

Turkey, 3.5 oz cooked

4.5

Pumpkin seeds, 1/4 cup

4.2

Wheat germ, 2 Tablespoons

2.4

Yogurt, low fat, 1 cup

2.2

Soy nuts, 1/4 cup

2.1

Almonds, 1/4 cup

2.0

Peanuts, 1/4 cup

1.7

Sunflower seeds, 1/4 cup

1.7

Shrimp, 3.5 oz cooked

1.6

Chicken, 3.5 oz cooked

1.3

Lentils, 1/2 cup cooked

1.3

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